^Galadriel Waters, Astre Mithrandir (2004). Ultimate Unofficial Guide to the Mysteries of Harry Potter: Analysis of Books 1-4. p. xviii. „("hepta = seven in Greek), but there is very little precedence for its use (and it doesn't appear in any dictionaries)”

Robert McCrum (22 iulie 2007). „The Hallows, and then the goodbyes: Tolkien it isn't, but J K Rowling's latest marks a triumphant literary achievement”. The Observer: p. 17. „The completion of this world-shaking heptalogy is something close to a triumph.”

„Section 3”. Musical News and Herald46: 610. January-June 1914. „So he has written his heptalogy, the titles of the dramas being "Lucifer", "Cain", "Magdalen", "Krishna", "Christos", "Psyche", and "Nirvana"" The title of the whole is The Cycle of Life...”.

Michael Ward. Planet Narnia. The Seven Heavens in the Imagination of C.S. Lewis. p. 13. „Charles Wrong ... reports Lewis as adding, "I had to write three volumes, of course, or seven, or nine. Those are the magic numbers."”

Ivanka Stoianova; Kohl (Winter 1999). „And Dasein becomes music: some glimpses of Light”. Perspectives of New Music37 (1): 179–212. doi:10.2307/833631. „Since 1977, the year which marks the beginning of the composition of the heptalogy Licht....”.

^Willard Thorp (1960). American Writing in the Twentieth Century. Harvard University Press. p. 174. „Here was stuff, not for a naturalistic trilogy but for a heptalogy! In the four novels which stand complete and in the fragment of a fifth (The Hills Beyond, 1941), Wolfe took one hero, Eugene Gant....”

^„Short List”. The Village Voice. 18 mai 1999. „Thornton Wilder left this heptalogy of one-acts unfinished at his death in 1975”

^Michael Moschos (25 septembrie 1992). „Obituary: Alexandros Kotzias”. The Independent Gazette: p. 31. „He completed four in this projected "heptalogy" under the general title "The Children of Kronos"”